From a users view

We use the short link to identify the location you refer to and to connect the tweet with the Twittori service. We do not use the domain http://www.twittori.com but the domain http://ge0.at just because it is shorter (minus 10 characters). The six characters that follow the domain name contain the whole geo location information. That means it is not done like tinyurl.com, bit.ly or is.gd do it by  adding a new reference to their database. Instead you can calculate the corresponding latitude and longitude of the position from the six characters itself. The following section describes how this is done.

From a technical view

Basically we use the Geohash algorithm for calculating our location hash. We just expanded this technique to use 64 characters in place of 32 characters. Here you can see the implementation in Javascript to calculate the latitude and longitude from the hash:

var BITS = [32, 16, 8, 4, 2, 1];
var BASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

function refine_interval(interval, cd, mask){
    if (cd & mask)
        interval[0] = (interval[0] + interval[1]) / 2;
    else
        interval[1] = (interval[0] + interval[1]) / 2;
}

function decodeGeoHash(geohash){
    var is_even = 1;
    var lat = [];
    var lon = [];
    lat[0] = -90.0;
    lat[1] = 90.0;
    lon[0] = -180.0;
    lon[1] = 180.0;
    lat_err = 90.0;
    lon_err = 180.0;

    for (i = 0; i < geohash.length; i++) {
        c = geohash.charAt(i);
        cd = BASE.indexOf(c);
        for (j = 0; j < 6; j++) {
            mask = BITS[j];
            if (is_even) {
                lon_err /= 2;
                refine_interval(lon, cd, mask);
            }
            else {
                lat_err /= 2;
                refine_interval(lat, cd, mask);
            }
            is_even = !is_even;
        }
    }
    lat[2] = (lat[0] + lat[1]) / 2;
    lon[2] = (lon[0] + lon[1]) / 2;

    return {
        lat: lat[2],
        lon: lon[2]
    };
}

I wrote a little demo to show this in action. Follow this link: http://www.twittori.com/geohash.html#0BOdWE

I had two rejections in this time:

1. I did not provide exact error messages when the Internet connection was not available and the geo positioning access was denied
2. The file was corrupt. I asked what that means and how I can avoid that for the future and did not get any repsonse

Since the last upload of the application I am waiting already more than a week and therefore I send the following email:

Hello,
the time is really running and I wonder how long it will take for the
approve of the Twittori app. Is there any estimate to help my planning?
Thanks,
Dirk

And I got the following response:

Dear Dirk,
Your application Twittori is still under review which is requiring unexpected additional time. While there is no additional information to share at this time, we wanted you to know it is still in process. We apologize for the delay, and will update you with further status as soon as we are able.
Thank you for your continued patience.
Regards,
iPhone Developer Program

I’m sorry about the delay of the apps release but as you can see this is not in my hands.

On Twitter I hear many other developers complaining about this behaviour of Apple. Let’s hope they get more transparent and faster. I think the developers deserve it, because they are the one that make the “there is an app for that” slogan possible!

1. Get your Mac running (sorry not available for other platforms)
2. Make sure you have installed the iPhone Simulator. If you don’t get it for free at http://developer.apple.com/iphone/ (you will need to have or create an login but you don’t need to be enrolled for the Developer Program)
3. Download the Twittori Preview App here: Download Preview
4. Unzip and double-click on the application to install it
5. Start your iPhone Simulator and enjoy

Feedback is welcome! Write to twittori@me.com

How is it possible? Well this is a great effort of Stefan Fürst from Media Atelier, Switzerland: http://www.grandtotal.biz/iPhoneSimulatorExchange/

• http://www.twittwoch.de/blog/2009/07/02/erste-bilder-vom-gestrigen-3-berliner-twittwoch
• http://www.slideshare.net/Twittwoch/twittori-tweets-aus-der-umgebung

Update:

Now the videos are also available. Please watch Part 4, 5 and 6. Attention, German only

• http://www.twittwoch.de/blog/2009/07/21/videos-des-twittwoch-vom-1-juli-2009-in-berlin-teil-1

Once you have send your UDID to twittori@me.com and your iPhone is registered we will send you a ZIP file containing two files:

1. A mobile provisioning file
2. The iPhone app

Drag both on the iTunes icon and sync your iPhone. Now the app should be available on the iPhone for testing.

The second unique feature is that users can follow places in a similar way than they are used to follow users on Twitter. Therefore the earth is divided in discrete squares of about 0.25 square kilometers. You can keep updated by subscribing to a RSS Feed or visiting the web site.

An iPhone application is also ready but not yet approved by the Apple App Store. In the meanwhile you can watch a little demo on the web site under the ‘iPhone’ menu entry.